Anthropogenic nitrogen enrichment enhances soil carbon accumulation by impacting saprotrophs rather than ectomycorrhizal fungal activity
Maaroufi, Nadia I. ; Nordin, Annika ; Palmqvist, Kristin ; Hasselquist, Niles J. ; Forsmark, Benjamin ; Rosenstock, Nicholas P. LU ; Wallander, Håkan LU
and Gundale, Michael J.
(2019)
In Global Change Biology
25(9).
p.2900-2914
- Abstract
There is evidence that anthropogenic nitrogen (N) deposition enhances carbon (C) sequestration in boreal forest soils. However, it is unclear how free-living saprotrophs (bacteria and fungi, SAP) and ectomycorrhizal (EM) fungi responses to N addition impact soil C dynamics. Our aim was to investigate how SAP and EM communities are impacted by N enrichment and to estimate whether these changes influence decay of litter and humus. We conducted a long-term experiment in northern Sweden, maintained since 2004, consisting of ambient, low N additions (0, 3, 6, and 12 kg N ha−1 year−1) simulating current N deposition rates in the boreal region, as well as a high N addition (50 kg N ha−1 year−1). Our... (More)
There is evidence that anthropogenic nitrogen (N) deposition enhances carbon (C) sequestration in boreal forest soils. However, it is unclear how free-living saprotrophs (bacteria and fungi, SAP) and ectomycorrhizal (EM) fungi responses to N addition impact soil C dynamics. Our aim was to investigate how SAP and EM communities are impacted by N enrichment and to estimate whether these changes influence decay of litter and humus. We conducted a long-term experiment in northern Sweden, maintained since 2004, consisting of ambient, low N additions (0, 3, 6, and 12 kg N ha−1 year−1) simulating current N deposition rates in the boreal region, as well as a high N addition (50 kg N ha−1 year−1). Our data showed that long-term N enrichment impeded mass loss of litter, but not of humus, and only in response to the highest N addition treatment. Furthermore, our data showed that EM fungi reduced the mass of N and P in both substrates during the incubation period compared to when only SAP organisms were present. Low N additions had no effect on microbial community structure, while the high N addition decreased fungal and bacterial biomasses and altered EM fungi and SAP community composition. Actinomycetes were the only bacterial SAP to show increased biomass in response to the highest N addition. These results provide a mechanistic understanding of how anthropogenic N enrichment can influence soil C accumulation rates and suggest that current N deposition rates in the boreal region (≤12 kg N ha−1 year−1) are likely to have a minor impact on the soil microbial community and the decomposition of humus and litter.
(Less)
- author
- Maaroufi, Nadia I.
; Nordin, Annika
; Palmqvist, Kristin
; Hasselquist, Niles J.
; Forsmark, Benjamin
; Rosenstock, Nicholas P.
LU
; Wallander, Håkan
LU
and Gundale, Michael J.
- organization
- publishing date
- 2019-06-05
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- carbon sequestration, ecological stoichiometry, Gadgil effect, high-throughput sequencing, ingrowth mesh bags, ITS amplicons, litter decomposition, root exclosure, soil organic matter
- in
- Global Change Biology
- volume
- 25
- issue
- 9
- pages
- 2900 - 2914
- publisher
- Wiley-Blackwell
- external identifiers
-
- scopus:85068798269
- pmid:31166650
- ISSN
- 1354-1013
- DOI
- 10.1111/gcb.14722
- language
- English
- LU publication?
- yes
- id
- 5d9270ac-9ad9-40ba-8f74-9b4b65b78306
- date added to LUP
- 2019-07-24 16:34:25
- date last changed
- 2024-12-26 19:29:22
@article{5d9270ac-9ad9-40ba-8f74-9b4b65b78306,
abstract = {{<p>There is evidence that anthropogenic nitrogen (N) deposition enhances carbon (C) sequestration in boreal forest soils. However, it is unclear how free-living saprotrophs (bacteria and fungi, SAP) and ectomycorrhizal (EM) fungi responses to N addition impact soil C dynamics. Our aim was to investigate how SAP and EM communities are impacted by N enrichment and to estimate whether these changes influence decay of litter and humus. We conducted a long-term experiment in northern Sweden, maintained since 2004, consisting of ambient, low N additions (0, 3, 6, and 12 kg N ha<sup>−1</sup> year<sup>−1</sup>) simulating current N deposition rates in the boreal region, as well as a high N addition (50 kg N ha<sup>−1</sup> year<sup>−1</sup>). Our data showed that long-term N enrichment impeded mass loss of litter, but not of humus, and only in response to the highest N addition treatment. Furthermore, our data showed that EM fungi reduced the mass of N and P in both substrates during the incubation period compared to when only SAP organisms were present. Low N additions had no effect on microbial community structure, while the high N addition decreased fungal and bacterial biomasses and altered EM fungi and SAP community composition. Actinomycetes were the only bacterial SAP to show increased biomass in response to the highest N addition. These results provide a mechanistic understanding of how anthropogenic N enrichment can influence soil C accumulation rates and suggest that current N deposition rates in the boreal region (≤12 kg N ha<sup>−1</sup> year<sup>−1</sup>) are likely to have a minor impact on the soil microbial community and the decomposition of humus and litter.</p>}},
author = {{Maaroufi, Nadia I. and Nordin, Annika and Palmqvist, Kristin and Hasselquist, Niles J. and Forsmark, Benjamin and Rosenstock, Nicholas P. and Wallander, Håkan and Gundale, Michael J.}},
issn = {{1354-1013}},
keywords = {{carbon sequestration; ecological stoichiometry; Gadgil effect; high-throughput sequencing; ingrowth mesh bags; ITS amplicons; litter decomposition; root exclosure; soil organic matter}},
language = {{eng}},
month = {{06}},
number = {{9}},
pages = {{2900--2914}},
publisher = {{Wiley-Blackwell}},
series = {{Global Change Biology}},
title = {{Anthropogenic nitrogen enrichment enhances soil carbon accumulation by impacting saprotrophs rather than ectomycorrhizal fungal activity}},
url = {{http://dx.doi.org/10.1111/gcb.14722}},
doi = {{10.1111/gcb.14722}},
volume = {{25}},
year = {{2019}},
}